1. Technical Field
This invention relates to digital timing circuits and, more particularly, to devices for making real-time measurements.
2. Discussion
Timing circuits are used in a variety of different applications to provide real-time measurements of events that occur in the real world. Time code receivers and time code generators use digital counters clocked by a high speed reference oscillator signal. This causes the time measurement resolution to be limited by the clock frequency of the time code receiver. Sometimes it becomes necessary or desirable to obtain real time values more accurate than the resolution of a given digital clock. Increased resolution may be obtained by employing additional high speed counters clocked by a phase lock loop oscillator (PLL) operating at a multiple of the frequency of the time code receiver (TCR) or time code generator (TCG) reference oscillator. However, the resolution of such a circuit is ultimately still limited by the time period of the highest frequency clock. Despite the long felt need, it does not appear that the prior art has proposed a solution to the problem with the simplicity and the resolution obtainable by the present invention.